在使用Python操作Neo4j数据库的时候,经常会遇到重复的节点,需要将一个节点的属性复制到另一个节点,之后将该节点删除。
def copy_node_properties(source_node_id,target_node_id,graph=None):
"""
将节点 source_node_id 的属性复制到节点 target_node_id 上面
"""
if source_node_id is None or target_node_id is None:
return
if graph is None:
graph = get_graph()
#将源节点的所有的内容合并到目标节点
match = "match (x) where id(x)= %s or id(x)=%s return x " % (source_node_id,target_node_id)
result = graph.run(match).data()
if result is not None and len(result) == 2 and result[0]["x"] is not None and len(result[0]["x"].nodes) > 0 and result[1]["x"] is not None and len(result[1]["x"].nodes) > 0:
n1 = result[0]["x"].nodes[0]
n2 = result[1]["x"].nodes[0]
to_merge_node = n1 if n1.identity == target_node_id else n2
source_node = n1 if n1.identity == source_node_id else n2
#复制标签到目标节点
target_node_labels = []
if to_merge_node.labels is not None:
for a in to_merge_node.labels:
target_node_labels.append(a)
to_add_labels = []
if source_node.labels is not None:
for a in source_node.labels:
if a not in target_node_labels:
temp = "set x:" + a
to_add_labels.append(temp)
#复制属性信息
fields = []
for k,v in source_node.items():
if v is None:
continue
if k in to_merge_node:
if to_merge_node[k] is None:
continue
if to_merge_node[k] == v:
continue
max = v if len(v) > len(to_merge_node[k]) else to_merge_node[k]
min = v if len(v) < len(to_merge_node[k]) else to_merge_node[k]
v = max if max.find(min) >= 0 else to_merge_node[k] + "/" + v
temp = "set x.%s = '%s'" % (k,v)
fields.append(temp)
if len(fields) ==0 and len(to_add_labels)==0:
return True
fields_str = " ".join(fields)
labels_str = " ".join(to_add_labels)
match = "match (x) where id(x)= %s %s %s return x " % (target_node_id,labels_str,fields_str)
result = graph.run(match).data()
if result is not None and len(result) > 0:
return True
else:
return False
return
